Method of sealing cartons



M y 1969 w. c. o. LINDSTRCSM 3,443,354

METHOD OF SEALING CARTONS Original Filed April 17. 1964 Sheet of2 INVENTOR Wictor c.o. Lindstrirh BY W 740147 ATTORNEY y 1969 w. c. o. LINDSTROM 3,443,354

' METHOD OF SEALING CARTONS Original Filed April 17, 1964 Sheet 2 of 2 INVENTOR Wictor C. O. L-indstr'o'm ATTORNEY United States Patent 3,443,354 METHOD OF SEALING CARTONS Wictor Carl Olaf Lindstriim, Gothenbnrg, Sweden, assignor to Jagenburg & Medin AB, Boras, Sweden Original application Apr. 17, 1964, Ser. No. 360,676, now Patent No. 3,355,085, dated Nov. 28, 1967. Divided and this application Nov. 29, 1966, Ser. No. 610,709

Int. Cl. B65b 7/20 U.S. C]. 5347 8 Claims ABSTRACT OF THE DISCLOSURE This is a division of copending parent application Ser. No. 360,676, filed Apr. 17, 1964, by the present applicant for a Sealed Carton, and the priority dates thereto are claimed for all subject matter common therewith. The parent application has matured into U.S. Patent No. 3,355,085.

This invention relates to sealed cartons, especially for frozen foods, and is, more specifically, concerned with cartons of the type made of an integral blank folded up to constitute a box-shaped bowl for receiving goods, and a hinged lid folded down and sealed against the mouth of such bowl or box.

Ca rtons of this type, when used for frozen foods, should be completely liquid-tight in order to prevent leakage of water or other liquid therefrom when the frozen products are thawed.

A primary object of my invention is, therefore, to provide a carton of the type referred to which can be easily and rapidly sealed in a liquid-tight manner.

Another object is to provide a carton of the type referred to, in which an effective liquid seal is provided at the corners of the lid of the carton, when closed.

Another object is to provide a carton in which all such joints which might otherwise constitute an escape for liquid, are caused to end blindly when the lid is sealed to the body of the carton.

A further object is to provide a blank adapted to be folded and sealed to constitute a liquid-tight carton.

Still another object is to provide a new and useful method of sealing cartons of the type referred to.

The invention will be described in detailed hereinafter, reference being had to the accompanying drawings, in which:

FIG. 1 is a view of a blank for a carton in accordance with this invention,

FIG. 2 is a perspective view of the carton after foldingup of its box-shaped portion, the lid being, however, open,

FIG. 3 is a perspective view of the closed and sealed carton, certain parts being broken away,

FIG. 4 is a perspective view of a carton with strips of adhesive film applied thereto, before bending down of the flaps of the lid, and

FIG. 5 is a sectional view of one wall of the carton and adjacent portions thereof.

The blank shown in FIG. 1 is preferably made of cardboard coated with a thermo-sealing plastic, such as polyethylene, and is by means of folding lines divided into a bottom portion 1, a lid portion 2, and rectangular panels 37, of which the panel 5 constitutes One wall of the carton and is situated between the bottom portion 1 and the 3,443,354 Patented May 13, 1969 lid portion 2 so as to unite them with each other. The other walls are constituted by the panels 3 and 4. Square corner areas 8 and 9 which are integral with the wall panels 3, 4 and 5 are situated between the lateral edges thereof and are provided with diagonally extending folding lines 10. Thus the wall panels 3-5 and the corner areas 8 and 9 constitute an integral strip around the bottom portion 1.

Extending along the free edges of the walls 3 and 4 and integral therewith are hinged strips or flaps 11 and 12, respectively, of which at least the strips 12 are extended along the corresponding free edges of the adjacent corner areas 8 and 9. In the example shown, the strip 11 is similarly extended.

The flaps 6 and 7 of the lid 2 are separated from each other through angular corner recesses 13 and from the corner areas 9 through linear incisions or slots.

In use, wall panels 3-5 are folded up to the positions shown in FIG. 2, the corner areas 8 and 9 being at the same time folded and glued or heat-sealed to the inside walls 3 and 5, respectively. The portions 12a of the strips 12 which, through this operation, are caused to lie flat against the inside of the lid 2, are glued or heat-sealed to the latter.

The carton may now be filled with goods and closed, the lid 2 being folded down onto the box-like portion of the carton and the strips 11 and 12 turned in over the same, as shown in FIG. 3. The lid 2 is glued or heat sealed to these strips 11 and 12, whereas the lid flaps 6 and 7 are glued or heat-sealed to the walls 3 and 4, whereby a liquid-tight sealed carton is provided.

Obviously, the body of the carton, constituted by the bottom 1, walls 3, 4 and 5, and folded corner areas 8 and 9, is integral and liquid-tight so that, When the lid is closed, any escape of liquid can only take place through the joints or seams between the lid and the body of the carton. Along the edges of the lid, sealing of these joints or seams constitutes no serious problem, the lid being glued or welded to the inturned flaps 11 and 12, whereas in cartons known heretofore, difficulties will arise at the corners of the lid where capillary openings will be formed at the points indicated by arrows a in FIG. 3. However, in the carton of this invention, such capillary openings are barred by the strips or flaps 12 extending integrally around the corners of the carton.

On the other hand, due to the strips 12 being bent down upon themselves at the corners of the carton, capillary channels may be formed at the places indicated by arrows b when the lid is glued or heat-sealed to the strips 11 and 12. For barring such channels, the lateral flaps 6 of the lid are provided, whereby the channels will end blindly at the inside of the flaps 6 when the latter are glued or heat-sealed to the walls 4.

A preferred closing operation for the carton of this invention is illustrated in FIGURES 4 and 5. In these figures, 21 is the bottom of the carton, and 22 and 23 the walls and the lid thereof, respectively, the lid being hingedly connected with one wall. The free edges of the lid are provided with flaps 24 intended to be folded down along the walls 22 and cemented thereto. Each wall has a strip-shaped flap 25 at its upper edge for folding into the carton, as hereinbefore described.

In closing the carton, the lid 23 is folded down to engage the inturned flaps 25 of the walls, whereas the marginal flaps 24 of the lid are folded up, as shown in the drawings, to extend in alignment with the corresponding walls 22. This operation may be effected mechanically and automatically by means of suitable machinery constituting no part of the present invention. Subsequently, a continuous adhesive film or coating 26 is applied in a narrow zone extending on both sides of the joint between the walls 22 and the flaps 24. The adhesive film may consist of polyethylene, for example, and may be applied either in liquid form or in the form of an adhesive tape having adhesive properties on both sides. The application may be effected by causing the carton to move, in the condition illustrated in FIG. 4, past a stationarily mounted glue coating roller or a roll of adhesive tape. Alternatively, the glue coating roller or the tape roll may be moved along the sides of the carton. At the same time, another strip of adhesive film 27 is applied in similar manner to the walls 22 adjacent the lower edges thereof. Finally, the flaps 24 are folded down along the walls 22, as indicated through arrows A, and sealed thereto, heat being applied, if necessary.

I claim:

1. A method of sealing a carton having a bottom, upstanding walls integral therewith, a lid hingedly connected with one of said walls, inturned strip-shaped flaps along the upper edges of the other walls for engaging the lower side of said lid, and hinged flaps along the edges of said lid, said method comprising the steps of closing said lid to engage said in-turned flaps, bending up said hinged flaps of said lid to a position spaced angularly from said walls, covering the joint between said walls and said hinged flaps with a continuous strip-like adhesive film, and bending down said hinged flaps to seal them to said walls by means of said adhesive film.

2. A method as in claim 1, in which said adhesive film is applied in liquid form.

3. A method as in claim 1, in which said adhesive film is applied in the form of a tape having adhesive properties on both sides thereof.

4. A method of sealing a carton having a bottom, upstanding walls integral therewith, a lid hingedly connected with one of said walls, in-turned strip-shaped flaps along the upper edges of the other walls for engaging the lower side of said lid, and hinged flaps along the edges of said lid, said method comprising the steps of closing said lid to engage said in-turned flaps, bending up said hinged flaps of said lid to a position in alignment with said walls, covering the joint between said walls and said hinged flaps with a continuous strip-like adhesive film,

and bending down said hinged flaps to seal them to said walls by means of said adhesive film.

5. A method as in claim 4, in which said adhesive film is applied in liquid form.

6. A method as in claim 4, in which said adhesive film is applied in the form of a tape having adhesive properties on both sides thereof.

7. A method of sealing a carton having a bottom, upstanding walls integral therewith, a lid hingedly connected with one of said walls, in-turned strip-shaped flaps along the upper edges of the other walls for engaging the lower side of said lid, and hinged flaps along the edges of said lid, said method comprising the steps of closing said lid to engage said in-turned fiaps, bending up said hinged flaps of said lid to a position angularly spaced from said walls, applying an adhesive film to a narrow zone of said walls and said hinged flaps on either side of and covering the joint between said walls and said hinged flaps, applying an additional strip-like adhesive film to said walls adjacent said bottom, and bending down said hinged flaps to seal them to said walls by means of said adhesive films.

8. A method of sealing a carton having a bottom, upstanding walls integral therewith, a lid hingedly connected with one of said walls, in-turned strip-shaped flaps along the upper edges of the other walls for engaging the lower side of said lid, and hinged flaps along the edges of said lid, said method comprising the steps of closing said lid and cementing it to said in-turned flaps, bending up said hinged flaps of said lid to a position angularly spaced from said walls, covering the joint between said walls and said hinged flaps with a continuous strip-like adhesive film, and bending down said hinged flaps to seal them to said walls by means of said adhesive film.

References Cited UNITED STATES PATENTS TRAVIS S. McGEHEE, Primary Examiner. 

